Concern about AIDS in adolescents has led investigators to speculate about the role of alcohol in HIV transmission. Studies show that alcohol use often accompanies sexual activity, and may be associated with increased sexual risk taking as well. Such information is critical for designing interventions, which currently assume that adolescents are sober at the time of sexual decision-making. Adolescents who use alcohol during sex may require more concentrated intervention efforts, to the degree that they may engage in more risky forms of sexual behavior as well. The proposed research will provide information on the relationship of alcohol use to adolescent sexual behavior and the processes by which these behaviors may be linked. The study will test a model that has been developed to explain adolescents' use of alcohol proximal to sexual events, and their use of condoms during these events. The model describes three factors hypothesized to correlate with adolescents' alcohol use and sexual behavior: the situational context of the sexual event, expectancies regarding alcohol use and sexual behavior, and sociodemographic characteristics. The research will provide information about how the situational context of sexual events interacts with adolescents' expectancies about alcohol and sex, and how these factors operate in different gender and racial-ethnic groups. In addition, the research will examine dispositional and emotional factors that may be associated with the use of alcohol during sexual events. Prior to testing the model, a combined quantitative-qualitative methodology will be used in interviews with adolescents to identify critical dimensions of the situational context of sexual events. This information will be used to develop situation- specific instruments necessary for testing constructs in the model. The model will be tested in a sample of 2,700 male and female adolescents, ages 15 to 18 years, who are recruited from urban high schools with mixed- ethnicity populations. The results of the proposed study will provide a very detailed natural history of the co-occurrence of alcohol use and sexual behavior in adolescents, and will provide the specific knowledge about the social and cultural context of these events that is critical to the further development of effective, theory-based interventions to reduce HIV transmission in youth.